A dual detector b-ray imaging probe with c-ray background suppression for use in intra-operative detection of radiolabeled tumors

The basic concepts for a dual detector b` imaging probe incorporating a method of c-ray background suppression were evaluated. The test devices consisted of a 1.2 cm2 b` imaging CaF 2 (Eu) scintillator disk optically coupled to a 1.7 mm thick, area-matched transparent diffuser disk, which in turn was coupled to sets of 2]2 or 4]4 mm2 by 10 mm long BGO, GSO or LSO scintillators, which acted as both c-detectors as well as light guides for the CaF 2 (Eu) scintillation light, which in turn are attached to a fiber optic bundle coupled to a multichannel photomultiplier. Pulse shape discrimination allowed identification of the detector of interaction and coincidence between the two detectors allowed selection of b`-only events. This type imaging detector system was shown to be capable of producing high-resolution images of b` distributions while suppressing the events due to the 511 keV annihilation radiation background. GSO was found to be the detector of choice for this application. ( 1998 Elsevier Science B.V. All rights reserved.